1. Field of the Invention
The present invention relates to a laser machined slider and more particularly to a slider which is machined in a selected atmosphere, the selected atmosphere promoting high definition and high aspect ratio patterns during laser etching.
2. Background of the Invention
A slider is employed for supporting a write/read head with respect to a rotating disk in a disk drive so that the write/read head can record and play back signals on tracks on the disk. The slider is attached to a suspension arm which is, in turn, attached to an actuator for selectively positioning the slider over the tracks on the magnetic disk. When the disk is rotated the slider rides ("flies") on a cushion of air (an "air bearing") slightly off of the surface of the disk, the cushion of air being generated by the high-speed movement of the disk.
The slider is typically a block of hard material which has an air bearing surface (ABS) that faces the surface of the disk. One or more magnetic heads may be mounted on the slider, typically at its trailing edge. The ABS may be contoured to establish desired pressure gradients for positioning and stabilizing the slider above the surface of the disk. For instance, rails can be provided adjacent side edges of the slider to lower the height of the slider with respect to the surface of the disk. In some instances U-shaped rails are employed for creating a negative pressure gradient, which draws the slider even closer to the disk surface for a given suspension load.
In order for a slider to fly at low altitudes over the surface of a rotating disk the contour of the ABS must have high definition and a high aspect ratio. High definition means that the rails or other configurations at the ABS be substantially free of irregularities, such as unwanted protrusions, bumps, ridges or jagged edges.
Sliders are typically made of titanium carbide (TiC) aluminum oxide (Al.sub.2 O.sub.3) ceramic which has good wear quality. TiC--Al.sub.2 O.sub.3 may be machined by reactive ion etching (RIE) or ion milling. First, a layer of photoresist is formed on the ABS with a pattern of the desired shape. The ABS is then RIE'ed or ion milled to machine the desired configuration. The layer of photoresist is then removed. This process, which is normally done at the batch level, produces sliders which have high definition. However, this process does not produce high aspect ratios.
Another material which is being considered for sliders is amorphous carbon, also known as high density amorphous carbon (HDAC). Amorphous carbon wears extremely well and can be easily machined by laser etching. Since a laser beam can be patterned using a mask and suitable projection optics, there is no requirement for photoresist as required for RIE of TiC--Al.sub.2 O.sub.3 sliders. Very high aspect ratios can be achieved. Unfortunately, as the laser beam machines the ABS it heaps debris on the surfaces of the ABS adjacent the machined site, resulting in poor definition. This is caused by redeposition of the etched material which increases in thickness with the depth of the etch. This debris is unacceptable since it perturbs the air flow and leads to unwanted head-disk interactions. In order to minimize this problem ultrasonic cleaning is employed to remove debris. Even with ultrasonic cleaning some of the debris remains.